A few things thoughts & comments about Modern Times, to get you thinking.
1) As I said in class, all the buildup to the song at the end is because Charlie Chaplain's voice had never been heard on screen before.
2) What role does voice play in the film? At the beginning it seems like the only voices we hear are mechanically reproduced ones - that is, the owner of the plant speaks, but not in person - only over the intercom. Similarly, we have voices on the radio. Then at the end we also get the voices of the waiters and of Chaplain. What do you make of all that?
3) Note the strong hint that "The Gamin" is engaged in prostitution at the beginning.
4) All the material about labor strife, communism, etc. would have hit very hard in the 30s: Chaplain is engaging head-on with the labor issues which circulate around industrialism.
5) Think about the different technologies which are represented, and how they relate to the technologies of film itself.